1. Field of the Invention
The present invention relates to a file structure analyzing apparatus, a file structure analyzing method, and a program. More particularly, the invention relates to a file structure analyzing apparatus, a file structure analyzing method, and a program for analyzing the tree structure of files.
2. Description of the Related Art
Video materials are generally recorded to package media such as video tapes and are also captured and transferred by servers through diverse digital interfaces including SDI (Single Document Interface). Once captured by a server, a video material is handled as a file that may be transferred to or shared by other servers located on a network. In recent years, network-based data transmissions have taken place mostly through asynchronous transmission channels exemplified by the IP network. In such cases, the interchangeability between data files becomes critically important.
In view of the above circumstances, there have been proposed formats aimed at promoting file exchanges such as MXF (Material Exchange Format) based on the SMPTE (Society of Motion Picture and Television Engineers) 377M standard. An MXF file is a structured file made up of a file header, a file body, and a file footer. Metadata may be stored into any or all of the header, body, and footer as needed.
Specifically, the metadata stored into the file header is called header metadata. The header metadata is constituted not only by video edit information but also by metadata for content identification as well as metadata explanatory of scenes and shots. These kinds of metadata are used to express information typically constituting explanations of an entire program or descriptions of scenes on a scene-by-scene or shot-by-shot basis. Because the structure and content of an entire file can be grasped by referencing its header metadata, the header metadata may be detached from the file body and transmitted or analyzed.
When a file is transferred or handled otherwise, the header metadata of the file may be used to analyze the structure and content of the entire file. This makes it possible to verify or correct the consistency of the file. Generally, MXF files have their detailed logical structures expressed as a tree structure each. The header metadata of the MXF file is thus expressed as tree structure data illustratively for content identification. In the past, analyzing such tree structure data required that the entire header metadata be expanded collectively in an internal memory. Where the header data was enormous in size, as in the case of picture data or other huge information being stored as part of header metadata, it was often impossible to expand all header metadata simultaneously in the internal memory. That in turn made it impossible to analyze the tree structure data in question.
Illustratively, Japanese Patent Laid-open No. 2007-148751 (hereinafter referred to as Patent Document 1) discloses a technique whereby the structural description elements of header metadata are separated from its data elements so that only the separated structural description elements may be expanded in an internal memory for tree structure analysis. The disclosed technique is intended to analyze the tree structure independently of the size of the data elements.